Fuse plug



June 27, 1933. T, NEWMAN 1,916,127`

FUSE PLUG Filed Sept. 3, 1929 Patented June 27, 1933 THOIAS NEWMAN, F DBAYTON PLAINS, MICHIGAN FUSE PLUG Application led September 3, 1929. Serial No. 389,922.

My invention relates to a new and useful improvement in a fuse plug, and has for its ob ect the provision of a fuse plug whereby substitution of fuse plugs may be prevented so that only a fuse plug of the proper rating ma be used, thus adding a feature of safety an reducing considerably the hazard which may arise in the use of plugs which may be interchanged.

Another object of the invention is the provision of a fuse plug which will afford a nearly perfect dead front so that undue shorting of the circuit may be eliminated.

Another object of the invention is the rovision of a fuse plug so constructed an arranged that the use of conductors other than the pro r fusible strip is obviated.

Anot er object of the invention is the provision of a fuse plug of this class which will be simple in structure, economical of manufacture, and highly eiicient in use.

Other objects will appear hereinafter.

The invention consists in the combination and arrangement of parts hereinafter described and claimed.

The invention will be best understood by a reference to the accompanying drawing which forms a part of this specification and in which,

Fig. 1 is a central sectional view of the fuse pllg.

ig. 2 is a bottom plan view of the fuse plllig.

ig. 3 is a central sectional view ot an adaptor which may be used with the inven tion.

Fig. 4 is a top plan view of Fig. 3.

Fig. 5 is a view taken online 5--5 of Fig. 3.

lFig. 6 is a central sectional view of a socket constructed for accommodating a fuse plug embodying the invention.

Fig. 7 is a top plan view of Fig. 6.

The fuse plug comprises the casing 9 hav- 5 ing the recess 10 formed in its outer end and closed by the closure 11 which is held in position by the ring 12. This closure 11 may be 'formed from mica or other suitable transparent non-inflammable insulating material. The threaded metallic sheathing 13 embraces the periphery of the casing 9 and is adapted for threading into the socket in which the fuse plug is to be ositioned. The neck 14 of the plug is provi ed with a recess in which is seated the metallic cup-shaped contact member lhaving a stud 16 connected with 55 the fusible strip 17 which connects to the sheathing or peripheral contact 13.

1f the socket is to be constructed to accommodate the fuse plug set out in Fig. 1, the construction would be such as is illustrated in Fig. 6 in which the socket 34 is provided with the cylindrical socket forming member 35 having the metallic lining 36 threaded for reception of the threaded portion of the plug. A neck 37 projects centrally upwardly 55 from the base and embraces a boss 43 around which is positioned the metallic ring 42 electricallv connected to the contact or buss bar 41. The lining 36 is connected by the strip 39 to the terminal lo, the bolt 38 securing the 7 sheath 36 in osition.

In using t e plug, the member l5 will receive the boss 43 and engage the metallic ring 42 to establish the desired connection. The member 37 will engage the recess 18 sur- 75 rounding the neck 14 so that a durable and rml connected structure is provided.

With a fuse plug constructed in this manner, in view of the fact that the contact 42 is seated below the outer surface of the boss 43, 8 the use of coins or other similar metal articles to establish connection is revented. Similarly, the substitution of a di erent rating fuse plug is also prevented.

ln order to accommodate the invention for use on sockets which are now in use and which do not embody the features of the socket shown in Fig. 3, ll have provided an adaptor 20 which is provided with the metallic sheathing 24 for threading into the 90 socket. A neck 21 projects outwardly from the base of the adaptor and is adapted to engage in the recess 18 of the plug when the plug is threaded into the socket. The adaptor is first threaded into the socket until 95 the contact 33 which is formed integral with the angularly turned portion 32 of the ring 31 engages the contact in the socket. The boss 23 functions as does the boss 43.

ln order to prevent substitution of fuse plugs in the sockets now in use, I have provided a means for locking the adaptor in position. A pair of swingable dogs 26 and 29 are mounted on the lower surface of the adaptor 20 and engage in recesses 25 and 28, springs 27 and 30 serving to retain these dogs in outwardly project-ed position so that when the adaptor is threaded into the socket, the dogs will prevent a reverse position so that the adaptor cannot be removed and the construction ofthe fuse plug is thus determined which must be used in the socket.

IVhile I have illustrated and described the preferred forinof my invention, I do not Wish to limit myself to the precise details of structure shown but desire to avail myself of such variations and modifications as may come within the scope-ot1 the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patentis:

1. In combination, a fuse plug and a socket for the reception of the same, comprising: a plug insertable into said socket; a neck projecting centrally outwardly from said plug;

a recess surrounding said neck; a Contact positioned in a recess in the outer face of said neck and being recessed; a central projection extending upwardly from the base of said socket engageable in the recess in said contact; a contact surrounding said projection engageable with the contact on said pluO'.

2. In combination, a fuse plug and a socket for the recept-ion of the same, comprising: a, plug insertable into said socket; a neck projecting centrally outwardly from said plug; a recess surrounding said neck; a contact positioned in a recess in the outer face of said neck and being recessed; a central projection extending upwardly from the base of said socket engageable in the recess in said contact; a contact surrounding said projection engageable with the contact on said plug; and a neck projecting upwardly from the base of said socket for embracing said neck and engaging in the recess surrounding the same.

In testimony whereof I have signed the foregoing specication.

THOMAS NEIMAN. 

